The present invention relates to electronic control systems for devices, such as engine control modules for vehicles. More specifically, the invention concerns systems and methods for the re-calibration of the electronic control systems.
Electronic controls for remote devices are prevalent. In recent years, electronic controls have been applied to vehicles, and particularly to internal combustion engines used in a wide range of applications. The electronic control systems for the engine, or engine control modules (ECM), can monitor and control all functions of the engine.
To assist vehicle fleet owners in making the most economical use of their vehicles, the typical ECM includes a memory for recording the performance data for the engine operation. This data can then be extracted from the ECM by a diagnostic or service tool via a data uplink. In some cases, the service tool plugs directly into a port of the ECM and issues commands to the ECM to download data from the local memory. In other cases, an optical, infrared or RF port can be provided for remote transmission of the data to the service tool.
For some electronic control systems, a service tool can be used to reprogram the electronic controller, or in the case of a vehicle engine, the ECM. These field-programmable ECMs have enabled product enhancements to be made at a greatly reduced cost. For example, a single generic control module can be reprogrammed at various times for many different applications, without any changes to the physical configuration of the module. For instance, a truck may have a different engine rating for use as a long-haul vehicle versus use as a short-haul vehicle. These different ratings may require that the engine have different calibrations between the two applications. If the truck is changed from one use to the other, changes in engine settings can be transmitted to the ECM through the service tool directly by the tool operator. In other instances, the changes to the electronic control system, or ECM, can be downloaded to the service tool from an off-site location. This downloaded information can then be uploaded to the ECM at the location of the vehicle.
With these prior systems, a highly trained and knowledgeable service technician is required to recalibrate the electronic control system, depending on the desired application of the control system. The additional manpower required to perform recalibrations on an entire fleet of vehicles can be expensive. In addition, the manual recalibration process can be very time consuming; taking fleet vehicles out of commission for long periods of time. Consequently, there remains a need for a system and method that permits recalibration of remote electronic control systems, such as ECMs, that are more economical and efficient.
The present invention addresses the needs left unmet by prior recalibration systems and techniques. In one aspect of the invention, a fleet manager development tool, or computer, is provided with a data base containing information about the current calibration of existing electronic control systems. The fleet computer also maintains a database of new or updated calibrations for the electronic control system or the controlled component. In the case of a fleet of vehicles, the electronic control system can be an ECM that monitors and controls the operation of the vehicle engine.
In one feature of the invention, a vehicle can automatically initiate an upload/download sequence performed by the fleet computer. The sequence can be conducted with the aid of a separate recalibration tool that provides the data link between the fleet computer and the vehicle ECM. This upload/download sequence can be instituted when the vehicle enters a service area. A software routine resident on the fleet computer acknowledges the presence of the vehicle and commences routines for downloading data from the vehicle ECM and/or recalibrating the ECM and/or engine. A visual display in the service area directs the vehicle operator to perform a few simple acts to commence the upload/download process.
In accordance with one embodiment of the present invention, the software resident on the fleet computer can direct the upload of user-requested trip information from the vehicle ECM. If a recalibration is requested, either automatically or by the fleet manager, the software interrogates the ECM for the serial number of the associated controlled component, in this case the vehicle engine. This engine serial number is used to extract the recalibration history for the engine from a database contained in the fleet computer. The most recent calibration entry for the engine is identified and compared against a table of updated recalibration entries, also maintained by the fleet computer.
The table of recalibration entries can be obtained from a central site, such as the engine manufacturer. In one aspect of the invention, the engine manufacturer can make available updated calibrations for the engines that the manufacturer produces. These updated calibrations can be due to improvements in the engine control routines, the addition of new applications for existing engines, or the like. This updated calibration information can be downloaded by the fleet manager in a variety of ways and stored in memory for later reference.
If the extracted calibration history for the particular engine includes the most recent calibration update, no further recalibration is required. On the other hand, in accordance with the present invention, the absence of the manufacturer""s most recent calibration from the engine""s calibration history signals the fleet computer software to download the new calibration information to the electronic control system, or ECM. When the new information is downloaded, the calibration history for the engine is automatically updated and stored in the fleet computer database.
In a further feature of the invention, access to the ECM is limited to prevent unauthorized modifications to the engine control data or routines. Each ECM maintains a password in its local memory. At the fleet computer, a password library is maintained in memory that includes a series of acceptable passwords. In some embodiments, the password library can include a limited number of passwords used in chronological order. In accordance with this aspect of the invention, the ECM password is compared to every password in the library, not just the most recently used password. If a match is found, access to the ECM is granted, otherwise the software issues an error message and abandons the recalibration process. When access is granted, the newest password is loaded into the ECM for future security checks.
A further feature of the invention addresses the integrity of data uploaded from the ECM. In some cases, data or program errors are known to exist in vehicle controllers that may not have been corrected. The present invention contemplates software executed by the fleet computer that evaluates certain suspect dataxe2x80x94i.e., data that is known to have the potential for being corrupt or erroneous. The suspect data is reviewed to determine if certain indicia are present that indicate the data to be corrupt. If the indicia are present, a further determination is made as to whether the data error is correctable. Again, it is known in advance what data errors can and cannot be fixed, as well as the appropriate fixes, if they exist. Correctable errors are address by the software and non-correctable errors can result in nulling the affected data. In one specific feature of the invention, to the extent that the corrupt data is a result of software errors, the affected software is updated or corrected to prevent future occurrences of the corrupt data.
The present invention contemplates a software-based system for recalibrating an electronic control system, such as an ECM, for performing security checks and for evaluating the integrity of data uploaded from the ECM. This same software can be accessed by the fleet manager to administer the database of calibration information used in other subroutines. For example, the fleet manager can select certain available calibrations to be assigned to particular ECMs in the vehicle fleet. In addition, the software allows the fleet manager to define and assign various adjustment sets to vehicles and engines in the fleet. The adjustment sets provided further flexibility in controlling the performance of the engine or vehicle, and tailor the nature of the trip information obtained from the vehicle. The adjustment set updates can be applied to the vehicle ECM using the same protocol as applied to the recalibration data.
It is one object of the present invention to provide a substantially automatic software-based system and method for recalibration of an electronic control system. A further object resides in aspects that verify security features associated with the control system to prevent unauthorized modification or tampering.
One benefit of the present invention is that highly skilled technicians or personnel are not required to effect recalibration of a control system, such as an ECM. A further benefit is attained by features of the invention that permit automatic updating of the necessary calibration and adjustment changes, as well as access passwords and data integrity information.
These and other objects and benefits can be discerned from the following written description of preferred embodiments of the invention, together with the accompanying figures.